<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        input {
            border-bottom: 1px solid;
            border-top: 0;
            border-left: 0;
            border-right: 0;
        }
    </style>
</head>

<body>
    账号：<input type="text">
    密码：<input type="text">
</body>

</html>